1. Field of the Invention
The present invention relates to sign assemblies including a quadrilateral frame in which the sign element is detachably mounted. In particular, the present invention relates to a sign assembly mounted in an inwardly bowed position in such a frame.
2. Description of the Prior Art
It is extremely desirable to have a sign frame assembly wherein the sign element can be easily removed and replaced by another. This is extremely important in public exhibition places such as theaters and zoos that change their shows periodically or want to have the capability of emphasizing different features during different seasons. The sign frame assembly must therefore have the capability of allowing the sign element to be easily removed and replaced by another sign element and yet hide the manner in which the sign element is placed within the frame assembly from the viewing public so that unauthorized persons may not remove the sign element.
The prior art is replete with sign assemblies comprising holders with replaceable sign elements. However, these devices are of such construction that the sign can be removed with little ingenuity. One such example is included in the Wilds U.S. Pat. No. 2,730,825 wherein an elongated molding has undercut top and bottom lips which engage an outwardly bowed flexible sign element. The removal of the sign element is accomplished by a person grasping opposite edge portions of the sign element with thumb and forefinger.
In another sign assembly shown in the Duckro U.S. Pat. No. 2,935,804, the main body of the molding is concave in construction and the sign element is deflected inwardly into the curved concave formation. A groove running longitudinally behind the sign element and in the elongated molding allows a person to pull the sign element by grasping the sign element in front of the groove and pulling it out into a convex position and disengaging the sign element from the holder.
The Knox U.S. Pat. No. 3,041,761 shows a frame assembly wherein the flexible sign element is inserted into grooves of opposing sides. The sign element may be flexed either into a concave or convex position for a viewing effect. When flexed into the convex position, the viewing public may easily discern the engaging relationship between the flexible sign element and the frame and remove the sign element. When flexed into the concave position to hide the manner of mounting, the flexible sign element is hard to remove since the opposing edges of the sign element are placed deeply within the grooves of the opposing frame members.
The Swirsky U.S. Pat. No. 3,460,282 shows a device that holds opposing edges of photographs within grooves. The device has only two frame members and the photographs are slid into the grooves of the frame members. The manner in which the photograph is mounted is not hidden and would be obvious to the viewing public if the device was used as a sign frame assembly.